Machine for making heat sealed closure



1956 w. H. BOKENKROGER 2,729,149

MACHINE FOR MAKING HEAT SEALED CLOSURE Filed Oct. 8, 1952 I, 3 Sheets-Sheet 1 11 TTORNE 1 Jan. 3, 1956 w. H. BOKENKROGER MACHINE FOR MAKING HEAT SEALED CLOSURE Filed Oct. 8, 1952 3 Sheets-Sheet 2 BY %M/ d TTORNE 1 Jan. 3, 1956 w. H. BOKENKROGER 2,729,149

MACHINE FOR MAKING HEAT SEALED CLOSURE Filed Oct. 8, 1952 5 Sheets-Sheet 3 INVENTOR.

Wig/HA7 fliawmwaazw BY MW ATTORNEY fin type. bottom.

United States Patent vMACHINE FOR MAKING HEAT'SEALED CLOSURE William H. Bokenkrogeniflndson. Falls, N. Y., assignor to Union "Bag & Paper Corporation, New York, N. Y., .a corporation of New Jersey Application Qctoher 8,1952, Serial No. 313,659 4 Claims. (Cl. 93-27) The present invention relates to improvements in making heat sealed bags. More particularly it pertains to a method of and apparatus'for making heat sealed bottom closures on paper bags of theflat and square type.

Heat sealed flat and square bags have usually been made either by merely heat sealing the tube and leaving the end of 'thetube below the heat seal band as a fin without folding such end back against the face of the tube, or by making the bag in a conventional manner and then heat sealing across the bag, thus using a part of the fillable depth of the bag for the heat seal band and producing a In the firsttcase the bottom is left in rough form and, because the end is not turned up, this construction is usually only employed on small bags. In the second case a two step operation is required and, because of the double thickness of the folded bottom, heat sealing is slower and, more diflicult.

The present invention provides apparatus which will score and turn up thebottom end portion of the bag tube so that it is partially folded and projects upwardly from the face of the tube. While in this-position the turned-up end is heat sealed for a period required to apply a heat sealed .bandafter which. the fold is completed and the end portion is adhesively secured into its final position against the body of the tube. This avoids the tension and resistance against folding which occurred in conventional heat sealing where the bag tube was heat sealed in a flat condition, after which the bottom was sought to beturned up against the body of the tube. allows the bag bottom to be more securely held against the bag body particularly where heavier paper or duplex construction was employed. It further eliminates. the wrinkles prevalent in bottoms of bags made in this manner.

A further object of the invention is to provide apparatus which will make the heat sealed bottom closure on a bag in a continuous operation, at increased speed over the conventional manufacture and at alower operatingcost.

It is a further object'of the invention to provideapparatus which will make a" heat sealed bag which does not have the objectionable fin type bottom and has full depth of the inside of the bag, thereby allowing a shorter tube length and a consequent saving of material.

It is a further object of the invention to provide apparatus of the type described wellsuited to operate in a practical and efiicient manner.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the several steps and the relation of one or more of such steps with respect to each of the others, and the apparatus embodying features ofconstruction, combination of elements and arrangement of parts which are adapted to effect such steps,

It further a .rtractablevtype paste pad.16 (seeFigure 3). ,16 .picks :up paste from .a rotating wheel.17" which in 2,729,149 Patented Jan. .3, 1956 ice . of'the invention reference should be had to the following ,the present invention;

.Figure 2 is a, frontelevation of the apparatus shown in Figure 1 withthe forwarding and bottoming rolls and paste mechanismomitted;

.Figure 3 is-a vertical sectional view of the bottoming rolls and. heat sealing unit, with a bag in place;

[Figure 4 is aside elevational view of the bottoming .rolls and one station on theheat sealing cylinder; and

'Figure 5 is a vertical sectional 'view ofa portion of the ,pinch. rolls showing the pinch bars.

.Referringmoreparticularly to thedrawings there is shown, in 'Figure 1, a bag blankv10 which has been tubed, longitudinally seamed. and cut into abag length. This vbag blank .is being moved along by two ,pairs of forwarding-rolls ,11,to,a pair of.,cooperati ng bottoming rolls 12 and 13,.spring mounted onta frame member14 to permit bags of different'thickness topass between the rolls. The

upper bottoming roll.1'2,has,,a tucker blade 15;.and a re- This pad turn is fed paste from asecond wheel 18 rotating through the paste in the dish 19. Since theforegoing equipment .:is of.conventional; design it is not shown in further detail.

- Referring to Figure 3, it will be seen that as the bottoming rol-ls rotate the tuckerblade, 15 forces the bag blank 30' 35 o continue to rotate the paste pad 16 applies a line of paste .22 across theface of the blank. As theblank approaches the heat .sealing unit, the pressure of the jaws on the blank causes the bottom end toassume a position virtually perpendicular to the face of the blank and the face of the lower bottoming roll.

The heatsealing cylinder 23, shown in Figures 1 and 2,.is rotatably mounted on the framet'24 and is provided .with multiple heat sealing stations. By using a cylinder with multiple stations it permitsample sealing time before the bagpblank is removed from the cylinder for folding the bottom end into position and also allows a series of bags to .be heat sealed at the same time.

.Each'station, illustrated in Figures 3 and 4, has a heat cured thereto by screws26. This unit has a fixed lower ban27 which houses an electric cartridge heater 28 for cylinder shaft, which brushes are fed electric current. Cooperating with such lower bar 27 is a movable upper bar 31 pivotably mounted on ashaft 32. This upper bar has a sealing pad made up. of a rubber strip .33 enveloped -in a sheet 34 of material to which heat scalable coatings will not adhere when heat is applied, e. g. Teflon (polytetrafluorethylene coated or impregnatedv glass fabric). This sheet and rubber strip are held in place on the bar by means of a metal strip 35 secured to the bar by screws 36. Also :secured to the upperbar 31 is a bag support plate 37 running across the cylinder and virtually the same length as the bar. This plate isheld in place by screws 38 and spacers 39 whichqelevate it above the bar. Such plateserves to keep the bag-blank held in the heat seal- .ing unit inthe proper position when the side nippers of the-discharge rolls,.described hereinafter, pick the bag from the heat sealing cylinder. Theshaft 32 is provided with a torsion spring 4.0 which normally keeps the pad mounted on the upper bar 31 under pressure against the upper face of the lower bar 27. Shortly before the heat sealing station reaches a position opposite the bottoming rolls to receive a bag, the cam follower 41 rides against the edge of the cam plate 42, which is affixed by bolts 43 to a bracket 44 held to the frame 24 by screws 45. The cam follower acts through the lever 46 to rotate the shaft 32, thereby causing the upper bar 31, sealing pad 34 and support plate 37 to move upwardly out of the path of the bottom end of the bag blank held in the gripper jaws of the bottoming roll 13. As soon as the bottom end, projecting perpendicularly from the face of the bottoming roll, rests against the lower bar 27 of the heat sealing unit, the action of the cam follower against the cam plate causes the upper bar 31, sealing pad 34 and support plate 37 to move downwardly so that the bottom end is gripped between the pad and the lower bar 27 (see Figure 3). At the same time the gripper jaw 21 on the lower bottoming roll opens and releases the tucked-in bag blank. As the lower bottoming roll continues to rotate the gripper jaws remain open and are ready to receive the next bag. Each station also has a plate 47, curved to conform to the arc of the heat sealing cylinder, running across and atfixed to said cylinder by supporting members 48, 49 and 50. This plate prevents the bag blank from falling between the sides of the heat sealing cylinder.

The bag blank held between the upper and lower bars of the heat sealing unit is heated as the cylinder rotates so that when the blank reaches the discharge roll a heat sealed band has been applied across the bag blank, thereby sealing the tube closed. A cylinder of this type with various heat sealing stations assures a sufiicient heat sealing interval, even for bags with heavier walls, and at the same time permits several bags to be heat sealed at the same time, thereby providing a fast operation. This construction is a distinct advantage over the conventional methods of heat sealing either by carrying the blank between heated tapes or by holding it between jaws which are moved over a flat type of conveyor until the proper band is effected. The cylinder of the present machines does the operation quickly and efficiently and requires less space.

It will be noted that the bottom end of the bag blank has been turned up virtually perpendicular to the face of the blank at the time it goes into the heat sealing unit and is sealed and remains in substantially the same position throughout its entire period on the heat sealing cylinder. Sealing the bottom end of the blank in this manner facilitates folding such end into its final position against the body of the blank. This removes the tension and resistance against folding which occurs in conventional heat sealing where the bag blank is heat sealed in a flat condition and then the bottom end is turned through 180 against the body of the blank. In such conventional manufacture it is very diflicult to keep the bottom end secured by adhesive against the body of the blank. This is particularly true where heavier paper or duplex construction is used. By turning up the'bottom end before heat sealing it permits the various thicknesses of paper in the bottom end to shift and removes any slack prior to heat sealing. Consequently when the fold is finally completed there is virtually no chance for wrinkles to occur in the bag bottom, as is prevalent in conventional manufacture.

When the heat sealing unit carrying the bag reaches the discharge station the cam follower 41 rides against the edge of the cam plate 51 secured to the frame 24. This rotates the shaft 32 thereby raising the upper bar 31 and releasing the bottom end of the bag blank from the unit. At the same time a pair of side nippers 52, actuated by cam followers 53 passing over earns 54 on the discharge cylinder, close and hold the blank against such cylinder. This cylinder is made up of a series of discs 55' which can be moved together or apart on the rotatable shaft 56 for blanks of different width. The blank is carried around the discharge cylinder to forwarding rollers 57 mounted on a rotatable shaft 58, where the bottom end is pressed into position against the body of the blank and the blank is pinched between the rollers 57 and the discs and forwarded to the pinch rolls 59. To keep the bottom fold in proper folded position a pair of fingers 60, held to the frame by a shaft 61 and suitable mounting 62, project between the discs 55 and rollers 57 almost to the pinch rolls 59. There are also guide members 63 between the forwarding rollers 57 and the pinch rolls 59, which members are held in a suitable mounting 64 on a fixed shaft 65 secured to the frame. These members serve to support the bag blank and prevent it from collapsing downwardly.

The bag then proceeds to the pinch rolls 59, rotatably mounted on the shaft 66, which take the bag from between the fingers 6t) and members 63 and pinch the bag bottom. This pinching operation is performed by a pair of cooperating pinch bars 67 and 68, one being mounted across each roll. These bars contact the top and bottom faces of the bag at the bottom tuck or crease line along which the bottom end has been folded back against the body of the bag, as illustrated by Figure 5. In addition there is mounted in the upper pinch bar 67 a rubber pad 69 which contacts the portion of the bototm along the transverse heat sealed band. These pinch bars serve to firmly press the crease line and the heat sealed band so that the bottom will be properly finished before the bag enters the carrier belts 70. To carry the bag from the pinch rolls 59 to the belts 70 there are a series of guide members 71 held in a suitable mounting 72 on a fixed shaft 73 secured to the frame. The carrier belts 70, passing over suitable rollers, not only carry the bags to a catch box but also help to press the bags into finished condition. Where desirable the pinch rolls can be equipped with conventional scorers for applying score lines at the top of the bag to facilitate closing and at the bottom for easier opening.

The various portions of the machine are driven off the master gear 74 mounted on the shaft carrying the heat sealing cylinder. The bottoming rolls are driven by gears intermeshing with gears 75 and 76, the discharge cylinder by gear 77, the forwarding rollers by gears 76 and 79 and the pinch rolls by gears intermeshing with gear 80.

The operation of the invention will be apparent from the foregoing desc iption. By employing this invention paper bags of the fiat and square type may be provided with better heat sealed bottom closures more efficiently and quickly than under any known method or apparatus.

Since certain changes in carrying out the above method and in the construction set forth, which embody the invention, may be made without departing from its scope, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in a limiting sense.

It is also to be understood that the following claims are intended to cover all the generic and specific features of the invention herein described, and all statements of the scope of the invention which, as a matter of language, mi ht be said to fall therebetween.

Having described my invention, what I claim as new and desire to secure by Letters Patent is:

1. in a machine of the class described, means for conveying to bottoming rolls a tube having at least its interior surface heat sealable, cooperating bottoming rolls with a tucker blade in one which forces the tube along a predeterirnned transverse line into a pair of gri per jaws in the other, the pressure of the jaws causing the end portion of the tube to fold upwardly into a position substantially perpendicular to the body of the tube, a rotatable cylinder having a heat sealing unit mounted thereon, said unit having bars adapted to receive the end portion from the jaws while in folded up position and apply heat and pressure to said portion in said position during the rotation of the cylinder, means for removing the tube from the heat sealing unit after the end portion has been heat sealed, and means for completing the fold and securing the heat sealed portion against the body of the tube.

2. In a machine of the class described, means for conveying to bottoming rolls a tube having at least its interior surface heat scalable, cooperating bottoming rolls with a tucker blade in one which forces the tube along a predetermined transverse line into a pair of gripper jaws in the other, the pressure of the jaws causing the end portion of the tube to fold upwardly into a position substantially perpendicular to the body of the tube, a rotatable cylinder having a plurality of heat sealing units mounted thereon, each unit having bars adapted to receive the end portion from the jaws while in folded up position and apply heat and pressure to said portion in said position during the rotation of the cylinder, means for removing the tube from the heat sealing unit after the end portion has been heat sealed, and means for completing the fold and securing the heat sealed portion against the body of the tube.-

3. In a machine of the class described, means for conveying to bottoming rolls a tube having at least its interior surface heat scalable, cooperating bottoming rolls with a tucker blade in one which forces the tube along a predetermined transverse line into a pair of gripper jaws in the other, the pressure of the jaws causing the end portion of the tube to fold upwardly into a position substantailly perpendicular to the body of the tube, a heat sealing unit adapted to receive the end portion of the tube from the jaws of the bottoming rolls, said unit 30 having bars with the heat sealing faces disposed substantially normal to the body of the tube and adapted to grip the end portion of the tube while in folded up position and apply heat and pressure to said portion in said position, means for removing the tube from the heat sealing unit after the end portion has been heat sealed, and means for completing the fold and securing the heat sealed portion against the body of the tube.

4. In a machine of the class described, means for conveying therethrough a tube having at least its interior surface heat scalable, jaws for grippnig the tube along a predetermined transverse line, a blade cooperating with such jaws for tucking the tube into the jaws, the pressure of the jaws causing the end portion of the tube to fold upwardly into a position substantially perpendicular to the body of the tube, a rotatable cylinder having a heat sealing unit mounted thereon, said unit having bars adapted to receive the end portion from the jaws while in folded up position and apply heat and pressure to said portion in said position during the rotation of the cylinder, means for removing the tube from the heat sealing unit after the end portion has been heat sealed, and means for completing the fold and securing the heat sealed portion against the body of the tube.

References Cited in the file of this patent UNITED STATES PATENTS 2,333,440 Potdevin Nov. 2, 1943 2,353,402 Haslacher July 11, 1944 2,476,057 Mead July 12, 1949 2,648,263 Richens Aug. 11, 1953 

